Hypothalamic and pituitary dysfunction in obese males.
Previous studies have indicated dysfunction of the hypothalamic-hypophyseal axis in obesity. We have studied 12 obese males to further characterize the extent of this dysfunction. The hypothalamic-hypophyseal-gonadal axis is normal as determined by the testicular response to human chorionic gonadotropin (hCG), the pituitary response to 200 micrograms gonadotropin-releasing hormone (GnRH), and the hypothalamic-pituitary-testicular response to clomiphene. Although L-dopa suppresses prolactin normally, the ability of thyrotropin releasing hormone (TRH) to stimulate the release of prolactin and thyroid stimulating hormone (TSH) is blunted. These latter responses are inversely related to the degree of obesity. The response to chlorpromazine, a hypothalamic stimulus for prolactin secretion, is also blunted, and to a greater extent than the prolactin response to TRH. These data indicate that exogenous obesity in males is associated with more extensive hypothalamic and pituitary dysfunction than previously realized. The abnormalities with regard to prolactin and TSH release become progressively worse when body weight exceeds 200 percent of ideal. In addition, when evaluating pituitary function with regard to gonadotropin release, obese males may have an abnormal response to 100 micrograms GnRH but respond normally to 200 micrograms.
D000328:Adult; D002746:Chlorpromazine; D006063:Chorionic Gonadotropin; D005640:Follicle Stimulating Hormone / Q000097:blood*; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology*; D007980:Levodopa; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D009765:Obesity / Q000503:physiopathology*; D011388:Prolactin / Q000097:blood*; D013739:Testosterone / Q000097:blood*; D013972:Thyrotropin / Q000097:blood*; D013973:Thyrotropin-Releasing Hormone; D013974:Thyroxine / Q000097:blood
D006063:Chorionic Gonadotropin; D013739:Testosterone; D007980:Levodopa; D013973:Thyrotropin-Releasing Hormone; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013972:Thyrotropin; D013974:Thyroxine; D002746:Chlorpromazine